Large-volume content is stored in a content server in a broadcast station. Content to be broadcasted is transferred to storage in a transmission server, and is stored in preparation for the broadcast of a program.
FIG. 13 is a functional block diagram for explaining an operation of an existing transmission server.
As shown in FIG. 13, a transmission server 100 reads content of a program on the air from storage 101. The transmission server 100 transmits a video signal in a first system, which is decoded by a first decoder 30(#1), to a transmitting apparatus through, for example, an OA (on-the-air) line via an external switcher 220. At the same time, a second decoder 30(#2) reads and decodes next broadcast content data from the storage 101. An output signal from the second decoder 30(#2) is transmitted to a NEXT line of a switcher 230 as an output in a second system, and is in a standby status for airplay.
Since the decoder 30(#1) is connected to the OA line, the decoder 30(#1) turns off the internal buffer and outputs decoded data without buffering. The decoder 30(#2) is, however, connected to the NEXT line that prepares for the next OA, and turns on the internal buffer. In a case where a decoder has no internal buffer, the decoder is connected to an external output buffer 40(#m) via the switcher 220, and the external output buffer 40(#m) is connected to the switcher 230.
Moreover, the transmission server 100 further includes a plurality of decoders and stores standby content as second and third preliminary content as necessary. A broadcast station plays back the standby content to confirm whether the content is stored properly, or to search for a transmission start point in the content prior to the OA. The confirmation takes the same time as the broadcast of the content. Data is thinned out and decoded to thereby play back the data in a fast-forward playback, in order to reduce the confirmation time and check content easily. However, the method has a disadvantage in that a problem or deterioration of details may be missed. Alternatively, in an independent apparatus for playing back a video signal, two apparatuses such as decoders 30(#n and #n−1) alternately read the same data to thereby perform fast-forward playback or backward playback (see, for example, Japanese Patent Application Laid-open No. 2009-118432, contents of which are hereby incorporated by reference). However, the method has a problem in that a system configuration is large because an external buffer is connected via an external switcher, and switching or operation control is complicated, i.e., control of the fast-forward playback or the backward playback of the content recorded in the transmission server is difficult.
There has been a problem in that it is difficult to confirm content recorded in an existing transmission server by a fast-forward playback or a backward playback.
It is desirable to provide a video server for multi-channel output that is capable of reading stored video content data and transmitting the data to an OA line while performing fast-forward playback and backward playback of other stored video content data such that a user confirms the other stored video content data, and a video signal output control method by the video server.